Can't figure out dynamic code

I'm stuck at this one, which is probably easy to fix.

So far I have:

Sub ListSheets()

Dim ws As Worksheet
Dim x As Integer

x = 1

Sheets("Lijst medewerker").Range("A:A").Clear

For Each ws In Worksheets
Sheets("Lijst medewerker").Cells(x, 1) = ws.Name
x = x + 1
Next ws

Dim LastRow As Long
Dim str As String

str = Cells(2, 1).Value

With Sheets("Lijst medewerker")
LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row

With .Range("B2:B" & LastRow)
.Formula = "=VLOOKUP($B$1,'" & str & "'!C:H,6,FALSE)"

End With

End With

End Sub

Now the problem is: The VLOOKUP formula in B2:B has to change the Worksheet name (in A2:A) but keeps returning the sheet name in A2. The str part is wrong but I don't know how to fix this.
Does anyone have a solution? I'm not an expert in VBA programming so excuse me if this code is crap so far....

Roeldh,

You fixed the "str" as Cells(2, 1).Value, but don't change it, so as you work down Col B it always looks at A2. Enter str=str.offset(1,0) after each pass should do it.

Ochimus